Plague is a highly contagious bacterial disease caused by zoonotic bacteria called Yersinia pestis. It affects mammals, including humans. It is transmitted mostly by infected fleas or by direct contact through inhalation or ingestion of infected matter.

Historically, plague was known as Black Death and assumed pandemic proportions killing more than 50 million people worldwide and wiping out almost a quarter of the world’s population. Plague carries a high mortality rate of up to 60% among the infected victims.


Plague can present itself in 3 forms – Bubonic, Septicaemic and Pneumonic.

Bubonic plague is caused by bites of infected fleas. When fleas infected with Y. pestis bite an individual, the bacteria travel to the nearest lymph node via the lymphatic system, where they replicate. This causes severe inflammation and pain resulting in a swelling called bubo, that is characteristic of bubonic plague and hence the name.

Septicaemic plague is usually caused by direct transmission of the disease though infected material via cracks in the skin. It is transmitted directly via the bloodstream.

Pneumonic plague is caused by droplet infection and is very potent and virulent. However, this is not a very common form of plague.


Symptoms of plague are very similar to that of common flu - fever, headache, chills, nausea, weakness and vomiting. Bubonic plague is characterized by the bubo, septicaemic by gangrene and pneumonic by infection in the lungs.


Diagnosis of plague involves initial screening by clinical presentation of symptoms followed by other laboratory tests. The best way to screen for the disease is to examine blood and fluid samples for the presence of the bacteria. Some of the techniques used in diagnosis of plague are:

  • Blood tests to detect the presence of antibodies against plague
  • Culture tests on samples of the body fluids of the patient
  • Kidney and liver function tests


Plague is a highly infectious disease and spreads rapidly within the body. So immediate medical attention is very important, without which the person might succumb to the infection. If diagnosed in time, antibiotics and supportive therapy can save the patient. The treatment for plague involves careful administration of antibiotics such as Streptomycin, Tetracycline, Gentamicin, Ciprofloxacin and Chloramphenicol. Draining of lymph nodes as and when required is a procedure followed to remove toxic matter from the body. To prevent dehydration from loss of fluids, the patient is administered with intravenous drips.


Prevention is better than cure, more so in case of a dreaded disease like plague. To prevent the spread of the disease, it is important that caregivers wear masks, gloves and use sanitizers.


Some of the precautionary measures advised include:

  • Use of insecticides in and around the house
  • Keep away from dead rodents and even sick cats
  • Keep your surroundings clean to avoid infestation of fleas

Plague Outbreaks

When sanitation measures are not up to the mark, plague outbreaks can happen. The following measures are advised for managing outbreaks of plague:

  • Determine and destroy the source of infection
  • Alert health workers
  • Step up sanitation measures
  • Isolate patients and provide immediate treatment
  • Provide guidelines for proper disposal of a victim’s dead body